JP3915450B2

JP3915450B2 - Positive pressure can with polyhedral wall formed in the body and method for manufacturing the same

Info

Publication number: JP3915450B2
Application number: JP2001242947A
Authority: JP
Inventors: 一男大塚; 一元小幡; 直森下; 威人伊福
Original assignee: Toyo Seikan Kaisha Ltd
Current assignee: Toyo Seikan Kaisha Ltd
Priority date: 2001-07-06
Filing date: 2001-07-06
Publication date: 2007-05-16
Anticipated expiration: 2021-07-06
Also published as: JP2003020038A

Description

【０００１】
【発明の属する技術分野】
本発明は缶胴に、凹凸を形成した構成単位面を配列して立体感と剛性を与えた不活性ガスを含む内容物を充填した陽圧缶に関するものであり、より詳細には、缶胴に周状多面体壁を形成することにより立体感を与えるとともに持ち易く、しかも不活性ガスを含む内容物を充填することにより内圧で多面体壁の構成単位面の窪んだ部分が外方に膨らみ、多面体壁を表示しながらほぼ滑らかな面を形成する不活性ガスを含む内容物を充填した缶であって、多面体壁を胴部形成し缶胴の剛性を大きくし、しかも流通時の印刷表示の認識性を損なわない陽圧缶に関する。
【０００２】
【従来の技術】
従来、缶体の側壁に多面体壁を形成し、付加価値を高めるため多くの提案がなされている。
例えば、特開昭５３−１４３４８５号公報及び特公昭５４−７１０号公報に見られる提案は、缶体の側壁に刻線や凹凸を設けることにより、缶体の手による屈曲や圧潰を容易にするというものである。また多面体壁を有する缶に不活性ガスと飲料を充填した缶が知られており、本発明者は先に特開平８−２６２８６号公報に示すように、缶胴に凹凸のある多面体壁を形成しビールを充填し内圧によりパネル変形した缶を提案した。
【０００３】
【発明が解決しようとする課題】
本発明者による先の提案は、充填したビールの内圧によって缶胴パネルが膨らみ予め形成した多面体壁の窪み深さの小さくなった缶形状が、開封によって内圧がかからなくなると元の窪み深さの大きな缶胴パネル形状に復帰し、ビールの泡立ち改良や、缶外観の変化を楽しむという提案であった。しかしながら特開平８−２６２８６号公報による提案の缶では、ビールは充填後の加熱殺菌がなく缶詰製造時の缶内圧が低いので、充填時と開封時の窪みや形状の変化が少なくパネル変形による効果が小さいという欠点があった。
【０００４】
また従来の飲料用缶、食品缶等は胴部に印刷等の表示を行っているが、胴部にビードや多面体壁を形成し、剛性を大きくし缶の軽量化を図ろうとすると、印刷された表示や図案が歪んで見づらくなり外観や意匠性が劣る問う問題もあった。さらに、缶詰の流通時には缶胴がほぼ滑らかで印刷表示が見やすく、しかも飲料時には多面体壁を配置して立体感を与えたり、手で持ったとき持ち易くしたり、剛性を大きくしたり、滑りを防止することは知られていない。
【０００５】
本発明の目的は、缶詰の製造課程でかかる高い内圧を利用して、缶胴壁に形成した多面体壁の構成単位面の窪みが外方に膨らんで表面の凹凸が小さくなりほぼ滑らかであるが、多面体形状が缶胴部に表示された独特の外観を与え印刷表示も見やすく、缶が密封されているときは例えば缶の温度が室温に低下して缶内圧が下がってもこの形状が維持され、開缶すると凹凸が戻って意匠的な面白さを提供するとともに、缶が持ち易くなり、薄肉軽量であるが剛性が非常に大きくなって飲用時に缶が潰れるなどの好ましくない変形を防止した陽圧缶とその製造方法を提供することにある。
【０００６】
【課題を解決するための手段】
本発明は、
「１．金属板の絞りしごき加工により形成された缶胴と、缶底と缶胴の上端部に設けられた易開封性口を有する缶蓋またはキャップとからなる缶であって、缶胴の少なくとも一部に構成単位面と、構成単位面同士が接する境界稜線及び境界稜線同士が交わる交叉部を有し、該境界稜線及び交叉部は構成単位面に比べて相対的に缶外側に凸となっており、構成単位面は対向する交叉部間で窪んだ部分を有し、且つ構成単位面の周方向に隣り合った缶体軸方向配列が位相差をなしている周状多面体壁が形成されており、前記構成単位面の窪んだ部分は内容物を充填し缶の内圧を加えた状態では、内圧により膨らんで、次の式（１）、
０ｍｍ＜ｈ_１≦０．２ｍｍ（１）
（式中ｈ_１は内容物を充填し内圧を加えた状態での窪みの最大深さを示す）を満足する、ほぼ滑らかで且つ多面体壁を表示する面を形成し、開封すると次の式（２）、
０．５ｍｍ＜ｈ_２≦１．５ｍｍ（２）
（式中ｈ_２は開封後の窪みの最大深さを示す）
を満足する、窪んだ部分を有する構成単位面からなる多面体壁を形成する陽圧缶であって、該陽圧缶が内容物を充填後、缶内圧の最大値が４Ｋｇ／ｃｍ ^２以上７Ｋｇ／ｃｍ ^２以下の範囲となる加熱処理を行う缶であることを特徴とする多面体壁を胴部に形成した陽圧缶。
２．金属板の絞りしごき加工により形成された缶胴と、缶底と缶胴の上端部に設けられた易開封性口を有する缶蓋またはキャップとからなる缶であって、缶胴の少なくとも一部に構成単位面と、構成単位面同士が接する境界稜線及び境界稜線同士が交わる交叉部を有し、該境界稜線及び交叉部は構成単位面に比べて相対的に缶外側に凸となっており、構成単位面は対向する交叉部間で窪んだ部分を有し、且つ構成単位面の周方向に隣り合った缶体軸方向配列が位相差をなしている周状多面体壁が形成されており、前記構成単位面の窪んだ部分は内容物を充填し缶の内圧を加えた状態では、内圧により膨らんで、次の式（１）、
０ｍｍ＜ｈ _１ ≦０．２ｍｍ（１）
（式中ｈ _１は内容物を充填し内圧を加えた状態での窪みの最大深さを示す）を満足する、ほぼ滑らかで且つ多面体壁を表示する面を形成し、開封すると次の式（２）、
０．５ｍｍ＜ｈ _２ ≦１．５ｍｍ（２）
（式中ｈ _２は開封後の窪みの最大深さを示す）
を満足する、窪んだ部分を有する構成単位面からなる多面体壁を形成する陽圧缶であって、該陽圧缶が、窒素ガスを充填したものであることを特徴とする多面体壁を胴部に形成した陽圧缶。
３．前記缶胴の前記構成単位面の窪んだ部分は次の式（３）
０．８ｍｍ≦ｈ_０≦１．７ｍｍ（３）
（式中ｈ_０は内容物を充填する前の窪みの最大深さを示す）
を満足する、請求項１又は２に記載された多面体壁を胴部に形成した陽圧缶。
４．前記陽圧缶が、内容物として炭酸ガス含有飲料を充填し、充填後に加熱殺菌する缶である、請求項１に記載された多面体壁を胴部に形成した陽圧缶。
５．金属板の絞りしごき加工により形成された缶胴に、多面体の頂部に対応した突起と境界稜線に対応した凸条と構成単位面の窪んだ凹面に対応する凹面が形成された表面を有する内型を挿入し、多面体の交叉部及び境界稜線に対応した溝と、構成単位面の窪んだ凹面に対応する凸面の配列が形成された表面を有する外型を外方から当て、缶胴部を挟んで内型と外型を回転して押圧し缶胴部に多面体壁を形成した缶に、不活性ガスを含む内容物を充填し密封後、缶内圧の最大値が４Ｋｇ／ｃｍ^２以上７Ｋｇ／ｃｍ^２以下の範囲となる加熱処理を行って構成単位面の窪んだ部分を外方に膨らませて胴部表面に多面体壁を表示したほぼ滑らかな面とすることを特徴とする、多面体壁を胴部に形成した陽圧缶の製造方法。」
に関する。
【０００７】
本発明においては、前記構成単位面の窪んだ部分は、下記式（１）および（２）を満足するものであることが、缶の外観特性を高め持ち易さと剛性を向上する点で重要である。すなわち、前記構成単位面の窪んだ部分は内容物を充填し缶内圧を加えた状態では、内圧により膨らんで次の式（１）、
０ｍｍ＜ｈ_１≦０．２ｍｍ（１）
（式中ｈ_１は内容物を充填し内圧を加えた状態での窪みの最大深さを示す）
を満足する、より好適には０ｍｍ＜ｈ_１≦０．１５ｍｍを満足する、ほぼ滑らかで且つ多面体壁を表示する面を形成することが、缶胴の印刷表示が認識しやすく、独特の外観を与え意匠性に優れるという効果を奏している。また缶胴表面の凹凸が小さいので、缶の搬送にも適している。ｈ_１が０ｍｍ以下となると開封時の窪みの大きい状態へのパネルの復元性が悪くなり、ｈ_１が０．２ｍｍより大きいと、開封時の窪みの変化量が少なくなり、形状の変化の面白さに劣るし、開封前の印刷が見づらくなったり、搬送性に劣る。一方、前記構成単位面の窪んだ部分は、開封後は次の式（２）、
０．５ｍｍ＜ｈ_２≦１．５ｍｍ（２）
（式中ｈ_２は開封後の窪みの最大深さを示す）
を満足する、より好適には０．６ｍｍ＜ｈ_２≦１．０ｍｍを満足する、窪んだ部分を有する構成単位面からなる多面体壁を形成することによって、ｈ１とｈ２の差が大きくなり開封前後の窪みの変化量が大きくなるので、形状の変化による面白さに優れるという効果を奏する。そして飲用時には窪みのある多面体壁を配置して立体感を与えたり、手で持ったとき持ち易くしたり、剛性を大きくしたり、滑りを防止するという点でも優れている。ｈ_２が０．５ｍｍ未満であると開封前後での窪みの変化量が小さく、形状変化の面白さに劣る。ｈ_２が１．５ｍｍを越えると多面体パターンの成形が難しくなり、また開封後の印刷表示の外観に劣る。
【０００８】
また、前記構成単位面の窪んだ部分は次の式（３）
０．８ｍｍ≦ｈ_０≦１．７ｍｍ（３）
（式中ｈ_０は内容物を充填する前の窪みの最大深さを示す）
を満足する、より好適には０．８ｍｍ≦ｈ_０≦１．１ｍｍを満足する、ことが好ましい。ｈ_０が０．８ｍｍより小さいと、開封後の窪みの深さｈ_２が小さくなってしまい形状変化の面白さが少なくなる傾向がある。ｈ_０が１．７ｍｍを越えると多面体パターンの成形が難しくなり、また開封後の印刷表示の外観に劣る。
【０００９】
また本発明の陽圧缶は、内容物充填後、缶内圧の最大値あ４Ｋｇ／ｃｍ^２以上７Ｋｇ／ｃｍ^２以下、より好適には４．５Ｋｇ／ｃｍ^２以上６．５Ｋｇ／ｃｍ^２以下、の範囲となる加熱処理を行うことが好ましい。この範囲の内圧がかかることにより、缶胴に形成した構成単位面の窪みが外方に膨らみ凹凸が小さくなりほぼ滑らかな多面体形状が発現する。缶内圧の最大値が４Ｋｇ／ｃｍ^２未満であると窪みの張り出し量が少なく滑らかな形状が得にくい。一方、缶内圧の最大値が７Ｋｇ／ｃｍ^２を越えると、缶底のバックリングが発生しなり、缶の耐圧性に問題を生じる場合がある。なお、内容物を充填後、加熱処理によって、缶内圧の最大値が４Ｋｇ／ｃｍ^２以上７Ｋｇ／ｃｍ^２以下の範囲となると、缶胴に形成した構成単位面の窪みが外方に膨らみ凹凸が小さくなりほぼ滑らかな多面体形状が発現するが、一旦このパネルが膨らんだ状態になると、加熱が終了し缶温が下がり、缶の内圧が１Ｋｇ／ｃｍ^２程度にまで下がっても、パネルは膨らんだままで構成単位面の窪みは元の深い状態に戻らず、窪みの浅いほぼ滑らかな状態を維持する。開封によって、一気に内圧が抜けると窪みの深い状態に復元する。
【００１０】
また本発明の陽圧缶は、内容物として炭酸ガス含有飲料を充填し、充填後に加熱殺菌するものが、製造工程で高い缶内圧が得られるので、缶胴パネルが張り出しやすく好ましい。さらに本発明の陽圧缶は、窒素ガスを充填したものであってもよい。この場合、内容物自身が炭酸ガス等の不活性ガスを含有しないものでも、窒素ガスの圧力によって、高い缶内圧が得られるのでパネルを変形させることができる。
【００１１】
【発明の実施の形態】
本発明では、缶胴部に形成された周状多面体壁のパネリング変形を利用して、不活性ガスと内容物を充填し内圧のかかる陽圧缶の胴部の形状を充填後の密封状態と開封時で変化させ、形状の変化で注目を引くとともに立体感を表出し、持ち易さと剛性を向上させるものである。即ち、この周状多面体壁は、容器内側に向かう多数の窪んだ部分を有するものであるが、缶構成材がアルミニウム板やスチール板であり、しかも絞りしごき加工により胴部厚みが０．０８０〜０．１５０ｍｍに薄肉化されているため、不活性ガスを含む内容物の充填とその後の加熱殺菌による缶内圧の上昇によって、この窪んだ部分が容器外方に変形し、ほぼ滑らかな缶胴表面まで深さが減少し、缶胴全体としては膨張した形状になり加熱後室温に温度が低下してもこの状態に保持される。この状態で容器蓋に形成されている易開封性口の開封を行うと、容器外方に膨らんで滑らかな状態にある缶胴の多数の窪んだ部分が内容物の充填前の窪みの深い状態に復帰する。この復帰により、内容物が炭酸ガスのような不活性ガスを含む飲料の場合には、飲料に含まれている不活性ガスの気化が促進される。このように、表面が滑らかな状態から窪みの深い状態まで缶胴を積極的に変形させ、缶胴の立体感を変化させて形状の変化を楽しみまた注目をひくとともに、飲用時に多面体壁を現出させて持ち易さと剛性を向上させるのである。例えば内容物が飲料すなわち飲料缶では、飲料をそのまま缶から飲む場合も、コップ等に注いで飲む場合にも、特に缶が冷えている場合は結露によりすべり易いので持ち易くすることは重要であり、また缶が変形してこぼれることも防止しなければならない。一方、開封前は多面体壁の窪みを小さくし、印刷表示を見やすくしたり搬送性を高めることも大切である。
【００１２】
また、本発明による陽圧缶は、不活性ガスが充填され密封後の加熱により製造課程で高い缶内圧となる陽圧缶であって、缶内圧の最大値が３．５Ｋｇ／ｃｍ^２のビールに比べ高い内圧となる陽圧缶が好ましい。この高い内圧であると、充填とその後の加熱によって缶胴がほぼ滑らかで多面体壁が表出された状態となり、加熱後常温に戻り缶内圧が低下してもこの状態が保持される。したがって本発明で使用する缶は、充填時と開封後の形状は大きく変形し、剛性、グリップ性等が向上する。
【００１３】
本発明で使用する缶の缶胴部に形成された周状多面体壁について説明すると、この周状多面体壁は、構成単位面と、構成単位面同士が接する境界稜線及び境界稜線同士が交わる交叉部からなる。構成単位面とは、周状多面体壁の軸方向（容器高さ方向）及び／または周方向に反復して現れる単位面であり、この面は屈曲面、屈折面或いは複数の面の集合体である。構成単位面相互は、軸方向及び周方向に境界稜線を介して接しており、この境界稜線同士が交わる位置に交叉部、即ち頂点が存在する。
【００１４】
本発明で使用する缶は、境界稜線及び交叉部を構成単位面に比べて相対的に容器外側に突出させ且つこれと合い補うように構成単位面の少なくとも一部を容器内側に窪ましたこと及び構成単位面の周方向に隣合った容器軸方向配列を位相差をなした配列としなことが重要な特徴である。
【００１５】
周状多面体壁の上記配置では、周方向及び軸方向の任意の方向に、境界稜線及び交叉部から成る凸部と、構成単位面の少なくとも一部から成る凹部とが必ず交互になるような配置、即ち凸部−凹部−凸部−凹部といった繰り返し配置となっている。しかも、これらの凸部及び凹部は、構成単位面がガッチリしかも隙間無しに噛み合って形成されているため、缶体の胴壁が著しく薄肉であるにもかかわらず、剛性が大きく器壁の変形に対する抵抗も大きく、不活性ガスと飲料の充填による内圧及び缶の開封による減圧に際しても、器壁の変形（特に凹部）が缶の商品価値を損なわないばかりかむしろ商品価値を高める良好な変形となり、しかもこの凹部の変形は周状多面体壁全体にわたって生じるため、缶胴部は内圧により多面体壁を表示した滑らかな面となり開缶すると持ち易い凹凸が形成される。
【００１６】
図面に基づいて具体的に説明する。図１は本発明で用いる缶の基本構造及び形状の一例を示す。図１は本発明の缶の側面図、図２は図１の缶をＡ−Ａ′線で切断した部分側面断面図、図３は図１の缶をＢ−Ｂ′線で切断した水平断面図である。缶１０は、アルミ板の絞りしごき加工で形成されて上部開口の側壁部６及び閉塞底部７と、上端に巻締めにより設けられた蓋体８とから成っている。この側壁部６には周状に多面体壁が形成されており、この多面体壁は、構成単位面１と、構成単位面同士が接する境界稜線２及び境界稜線同士が交わる交叉部３を有し、該境界稜線２及び交叉部３は構成単位面に比べて相対的に容器外側に凸、構成単位面１の少なくとも一部５は相対的に容器内側に凹となっている。またこの多面体壁では、構成単位面１の隣合った容器軸方向配列が位相差をなした配列となっている。
【００１７】
図４は構成単位面の説明図であって、容器胴部に形成されている多面体壁中の１個の構成単位面を取り出して示したものであり、
図５は構成単位面の中央部の垂直断面を示す図である。図１の構成単位面１は、周方向に隣合った容器軸方向配列が丁度１／２の位相差をなして配列されている。図４における各辺ａｂ、ｂｃ、ｃｄ、ｄａは容器側面に形成される境界稜線２に相当する辺であり、外向きに凸となる頂点ａ、ｂ、ｃ、ｄが交叉部３に該当する。
【００１８】
上方頂点ａと下方頂点ｃとは同一径の円周面上に位置しており、左方頂点ｂと右方頂点ｄとは同一径の円周面上に位置している。配列が１／２の位相差をなしている場合、全ての頂点は同一径の円周面上に位置しており、図３に示す通り、これら頂点に対応する容器胴部内半径は、最大半径ｒである。一方、各稜線ａｂ、ｂｃ、ｃｄ、ｄａは交差点でもあるａ、ｂ、ｃ、ｄで径外方に最も突出しているが、交差点と交差点の中間に行くに従い容器の中心軸からの距離、即ち径が減少する。周方向の対角線ｂｄの中点の径ｓはｒより小さく、図３の場合最小内径を与える。
図４において構成単位面の頂点ａ、ｂは容器胴部の軸線に沿った同一直線上に配置されており、頂点ｂ、Ｃは容器胴部の同面の同一曲線上に配置されている。
そして、対角線ａ、ｃは、対角線ｂｃより径外方向に位置しており、四角形ａｂｃｄは対角線が最も径内方に凹んだ滑らかに湾曲した面となっている。
【００１９】
また図４において、構成単位面としての菱形寸法は、周方向対角線ｂｄの長さをｗとし、軸方向対角線ａｃの高さをＬとすると、ｗ及びＬはそれぞれ構成単位面の周方向最大巾及び軸方向の最大長さとなる。軸方向対角線の長さａｃ（高さＬ）に比して、実際の構成単位面上のａｃ断面での長さは長く、このａｃ断面は容器内側に滑らかに窪んだ曲線となっている。構成単位面上のａｃ断面の長さは、窪みの曲率半径Ｒが大きくなるにしたがって短くなる。
【００２０】
さらに各構成単位面において、周方向対角線ｂｄの長さ（ｗ）と、実際の構成単位面上のｂｄ断面での長さとが異なる場合がある。例えば図３では周方向対角線ｂｄと実際の構成単位面上のｂｄ断面とが一致していて、それらの長さが等しいが、この断面における辺ａｃの中点は、周方向対角線ｂｄの位置よりも径外方向に位置していたり、径内方向に位置している場合がある。
【００２１】
例えば図３及び図５に示す例では、ａｃ断面が滑らかに湾曲しており、ｂｃ断面は実質上ストレートであるが、他の具体例を示す図６においては、ａｃ断面もｂｄ断面も共に内方に滑らかに窪むように湾曲しているので長さが大きくなる。
【００２２】
本発明で使用する缶において、上述した周状多面体壁は缶胴の開口部近傍と底部近傍、つまり胴部の上部と下部を除いて胴部全面に配置されているが、缶胴の少なくとも２５％以上、特に６０％以上の割合で形成されていることが好ましい。８０％〜２５％形成されていることがさらに好ましい。この周状多面体壁が缶胴を占める割合が上記範囲よりも小さいと、缶の開封に際してのパネリング変形が小さくなり、缶胴に表出される多面体壁による形状の変化が少なくなって、立体感と剛性及び持ち易さの効果が劣化する。
缶胴の上部と下部に多面体壁を配置しないのは缶の製造工程、移送工程で胴部の上部と下部が治具に挾持されるので、この部分には多面体壁がない方が好ましい。
【００２３】
また容器胴部の周に存在する構成単位面の数は、少なくとも４以上であることが好ましい。即ち、この構成単位面の数が４よりも少ないと缶の開封に際してのパネリング変形による効果が小さくなるし、また多面体壁を胴部に形成する際に胴部面での曲げが激しくなるため、塗膜の耐腐食性が著しく低下し、外観も悪くなる。まな胴部に形成される多面体壁による模様も単調となり、剛性や缶の持ち易さも向上しない。このように多面体壁の形状変化による効果が小さくなる。
【００２４】
また一般的に言って、前記構成単位面の缶体軸方向最大長さＬ及び缶周方向最大長さｗは、それぞれ１乃至３ｃｍ、特に１．５乃至２．５ｃｍの範囲にあることが好適である。これらの長さＬ及びｗが、上記範囲よりも小さい場合には、前述した缶の開封に際してのパネリング変形を生じにくく、また上記範囲よりも大きいと、パネリング変形による効果が小さくなり、立体感、剛性及び持ち易さが向上しないおそれがある。
【００２５】
本発明においては、上述した缶の開封に際してのパネリング変形は、缶素材金属としてアルミニウムやスチール等の金属板を使用し、金属板の絞りしごき加工により形成された薄肉の缶胴に多面体壁を形成することにより生じるものであるが、このパネリング変形による不活性ガスを充填した陽圧缶の効果を促進させるために、陽圧缶開封前の構成単位面の窪んだ部分の最大深さと、陽圧缶の開封後の構成単位面の窪んだ部分の最大深さとの間に次の関係を満足させることが重要である。
【００２６】
即ち、図５に示す構成単位面の中央部の垂直断面図において、不活性ガスと内容物が充填密封された陽圧缶の開封前における構成単位面の窪んだ部分の最大深さをｈ_１、開封後の缶における構成単位面の窪んだ部分の最大深さをｈ_２としたとき、両者はそれぞれ、前記式（１）、（２）で規定する範囲内、すなわち
０ｍｍ＜ｈ_１≦０．２ｍｍ（１）
且つ０．５ｍｍ＜ｈ_２≦１．５ｍｍ（２）
にあることが重要である。より好適には、それぞれ０ｍｍ＜ｈ_１≦０．１５ｍｍ、０．６ｍｍ＜ｈ_２≦１．０ｍｍの範囲にあることが好ましい。
【００２７】
このｈ_１とｈ_２差は、缶の開封に際しての缶胴の変形の度合に相当するものであり、例えばｈ_１が上記範囲よりも大きいか、ｈ_２が上記範囲よりも小さくｈ_２とｈ_１の差が小さい場合には、缶の開封に際しての胴壁の窪み部分の戻りが小さくなるため、缶胴のパネリング変形による効果が小さくなる。またｈ_１が上記範囲よりも小さいと、不活性ガスの充填による缶胴の膨張が大きくなり過ぎて開封時のパネルの窪みの戻り変形が起こり難くなる。またｈ_１が上記範囲より大きくなると、多面体パターンの成形が困難となる。すなわち、上記範囲内にｈ_１、ｈ_２がある場合には、パネリング変形による効果が極めて高いものとなるばかりか、不活性ガスと内容物を充填密封した状態において、これ等を充填した陽圧缶に特異な立体感と美観とが付与され、商品価値も極めて高いものとなる。通常、缶胴側壁に窪みが深く屈折した部分があると、この部分が陰影となり易く、表面の印刷画像等を見ずらくし、装飾効果が低下して商品価値が損なわれる。一方、本発明にしたがって形成される多面体パターンでは、構成単位面が規則正しく組み合わされ、しかも不活性ガスと内容物の充填状態において、構成単位面はごく平面に近い状態で滑らかに窪んだものとなるため、商品価値の極めて高いものとなるのである。
【００２８】
また本発明による陽圧缶では、不活性ガスや内容物を充填する前における構成単位面の窪んだ部分の最大深さをｈ_０としたとき、ｈ_０は前記式（３）で規定する範囲内、すなわち０．８ｍｍ≦ｈ０≦１．７ｍｍの範囲、より好適には０．８ｍｍ≦ｈ_０≦１．１ｍｍを満足する範囲にあることが望ましい。このｈ_０も間接的に缶の開封に際しての缶胴の変形度合に影響するものであり、ｈ_０が０．８ｍｍより小さいと、開封後の窪みの深さｈ_２が小さくなってしまい形状変化の面白さが少なくなる傾向がある。ｈ_０が１．７ｍｍを越えると多面体パターンの成形が難しくなり、また開封前の印刷表示の外観に劣る。
【００２９】
上述した式（１）、（２）を満足するような変形を生じさせるためには、缶胴側壁６の厚みを０．１５０ｍｍ以下、特に０．０８０乃至０．１５０ｍｍとすることが好ましく、さらに不活性ガスを含む内容物を充填前の状態において形成されている構成単位面の窪んだ部分の曲率半径Ｒ
（ｍｍ）が、下記式（４）：
０．１≦Ｒ≦０．５（４）
特に下記式（５）
０．２≦Ｒ≦０．４（５）
を満足するように周状多面体壁を缶胴に形成することが望ましい。即ち、缶胴側壁６の厚みが上記範囲よりも厚い場合には、前述したパネリング変形を有効に生じないおそれがある。また窪んだ部分の曲率Ｒが、前記式で規定する範囲よりも小さいと、その窪みに加工時の折れ目が形成されるため、缶の外観が損なわれるばかりか、該折れ目にて側壁が折れ込む等の変形を生じ易くなり、さらに曲率Ｒが前記式で規定する範囲よりも大きいと、窪みの深さが浅くなって局部的な変形低効力が小さくなるため、前述した式（１）、（２）を満足するような適度な変形を生じさせることが困難となる。
【００３０】
また、本発明で使用する缶においては、構成単位面は四辺形に限定されず、特に菱形であることが好ましいが、他の多角形とする事ももちろん可能であり、例えば六角形とすることができる。図７は構成単位面が六角形である例を示す。この場合でも多面体の基本的構成は前述した場合と同じである。
【００３１】
本発明で使用する缶は、金属素材としてアルミニウム板やスチール板を使用し、金属板の絞りしごき加工により、薄肉の側壁部を有する缶体を成形し、これに周状多面体の刻設を行った後、飲料を充填後、巻締め加工により易開封性口を有する缶蓋を設けることにより製造される。
【００３２】
金属素材のアルミニウムとしては、所謂純アルミニウム以外にもアルミニウム合金を使用することができる。特に耐食性と加工性の点で優れたアルミニウム合金は、Ｍｎ：０．２乃至１．５重量％、Ｍｇ：０．８乃至５重量％、Ｚｎ：０．２５乃至０．３重量％、Ｃｕ：０．１５乃至０．２５重量％、残部がＡｌの組成を有するものである。これらアルミニウム乃至アルミニウム合金は、金属クロム換算で、クロム量が３乃至３００ｍｇ／ｍ^２となるようなクロム酸／リン酸処理が行われることが望ましい。スチールとしては冷延鋼板ないし箔に、錫メッキ、ニッケルメッキ、電解クロム酸処理、クロム酸処理等の表面処理の一種又は二種以上行ったもの等を用いることができる。
【００３３】
上記の金属素材を用いての缶体の成形は、素板をしぼりダイスとポンチとの間で一段乃至多段の絞り加工に付して側面無継目の有底缶胴を成形し、この胴部にしごきポンチとダイスとの間で一段乃至多段のしごき加工を行うことにより行われる。この絞りしごき加工は、最終的に薄肉化される胴部壁の厚みが前述した範囲、即ち０．１５０ｍｍ以下、特に０．０８０乃至０．１５０ｍｍの範囲となるように行うことが好ましい。一般的には、総絞り比が、１．８乃至２．５、特に２．０乃至２．３の範囲にあるのがよく、また下記式：
Ｒ_１＝１００×（ｔ_０−ｔ_１）／ｔ_０
式中、ｔ_０はしごき加工前の壁厚であり、ｔ_１はしごき加工後の壁厚である、で現されるしごき率（Ｒ_１）が５０乃至８０％、特に６０乃至７０％の範囲とするのがよい。
【００３４】
上記で形成された蓋を取り付ける前の缶体胴部への周状多面体の形成は、缶体胴部を、内型と外型とで型押して前記多面体を形成することにより行う。使用する内型は、前記多面体の頂点及び稜線に対応する突起を表面に有するものであり、一方使用する外型は、前記多面体の谷に対応する突起を表面に有するものであり、これらの内型及び外型を容器胴部を介して噛み合わせることにより、多面体の形成が行われる。
【００３５】
図８は、缶体胴部への多面体刻設の方法を示す説明図であるが、理解が容易なように缶体胴部の一部を切り欠いた状態で示してある。この例では構成単位面が四辺形の場合を示したが、構成単位面が四辺形以外の場合でも原理的にこれと変わりがない。缶体胴部１０は内型１１及び外型１２に挟まれた状態で回転される。内型１１の表面には、多面体の頂点に対応した突起１３及び境界稜線に対応した突条１４と、構成単位面に対応する窪んだ凹面１５とが形成されている。一方、外型１２の表面には、多面体の交叉部及び境界稜線に対応した溝１６と、構成単位面に対応する凸面１７が形成されている。
【００３６】
これらの内型１１と外型１２とを缶体胴部１０を介して噛み合わせ、且つこれらを同期した速度で回転させることにより、容器胴部への多面体の刻設が行われる。尚、回転に際して一部に噛み合わせがずれる場合には内型或いは外側の回転軸が若干上下動するようにしてもよい。
【００３７】
図８に示す具体例において、内型１１及び外型１２は、缶体胴部１０よりも小さい径を有しているが、内型１１と外型１２の表面における基本面構成単位の周方向への配置数は缶体胴部周囲のそれに比べて１個或いは複数個少ないものとして構成単位面の配列の開始点部と終点部で配列がオーバーラップして成形されるので凹凸が明確となる。内型１１と外型１２とを離すことにより、多面体刻設缶体胴部の取り出しが容易に行われる。
オーバーラップさせることにより開始点部と終点部も確実に成形され、凹凸が設けられない継ぎ部は生じない。
【００３８】
本発明で使用する缶は、多面体刻設に先立った何れかの段階或いは多面体パターン刻設後に、素材金属板或いは缶体に樹脂の保護被覆を施すことができる。保護被覆の形成は、保護塗料を設けることにより、或いは熱可塑性樹脂フイルムをラミネートすることにより行われる。
【００３９】
保護塗料としては、熱硬化性及び熱可塑性樹脂からなる任意の保護塗料：例えばフェノール−エポキシ塗料、アミノ−エポキシ塗料等の変性エポキシ塗料：塩化ビニル−酢酸ビニル共重合体、塩化ビニル−酢酸ビニル共重合体部分ケン化物、塩化ビニル−酢酸ビニル−無水マレイン酸共重合体、エポキシ変性−、エポキシアミノ変性−或いはエポキシフェノール変性−ビニル塗料等のビニルまたは変性ビニル塗料：アクリル樹脂系塗料：スチレン−ブタジエン系共重合体等の合成ゴム系塗料等の単独または２種以上の組合せが使用される。
【００４０】
これらの塗料は、エナメル或はラッカー等の有機溶剤溶液の形で、或は水性分散液または水溶液の形で、ローラ塗装、スプレー塗装、浸漬塗装、静電塗装、電気泳動塗装等の形で金属素材に施す。勿論、前記樹脂塗料が熱硬化性の場合には、必要により塗料を焼付ける。保護塗膜は、耐腐食性と加工性との見地から、一般に乾燥状態で２乃至３０μｍ、特に３乃至２０μｍの厚みを有することが望ましい。また、加工性を向上させるためには、塗膜中に、各種滑剤を含有させておくことができる。
【００４１】
ラミネートに用いる熱可塑性樹脂フイルムとしては、ポリエチレン、ポリプロピレン、エチレン−プロピレン共重合体、エチレン−酢酸ビニル共重合体、エチレン−アクリルエステル共重合体、アイオノマー等のオレフィン系樹脂フイルム、ポリエチレンテレフタレート、ポリブチレンテレフタレート、エチレンテレフタレート／イソフタレート共重合体等のポリエステルフイルム：ナイロン６、ナイロン６，６、ナイロン１１、ナイロン１２等のポリアミドフイルム：ポリ塩化ビニルフイルム：ポリ塩化ビニリデンフイルム等を挙げることができる。これらのフイルムは未延伸のものでも、二軸延伸のものでもよい。その厚みは、一般に３乃至５０μｍ、特に５乃至４０μｍの範囲にあることが望ましい。フイルムの金属素材への積層は、熱融着法、ドライラミネーション、押出コート法等により行われ、フイルムと金属箔との間に接着性（熱融着性）が乏しい場合には、例えばウレタン系接着剤、エポキシ系接着剤、酸変性オレフィン樹脂系接着剤、コポリアミド系接着剤、コポリエステル系接着剤を介在させることができる。
【００４２】
蓋体としては、缶体と同じアルミニウム製のものが使用され、また蓋体の形状等は従来公知のものであり、例えばスコアにより易開封性口が形成され、タブ等により易開封性口の開封を行うものである。またキャップとしては、アルミニウム製やプラスチック製のものが好適に使用でき、形状等は従来公知のものでよい。かくして形成される不活性ガスと内容物を充填した陽圧缶においては、充填された不活性ガスの缶内圧により、周状多面体の構成単位面における窪み部分が、不活性ガスの充填前に比して缶外方に膨張変形しているが、この変形部分は缶の開封により不活性ガスと内容物充填前の状態にパネリング変形して復帰する。
本発明で不活性ガスと充填する内容物としては、例えば炭酸飲料、炭酸ガス含有の焼酎、酎ハイ、スピリッツ、リキュール類等のアルコール飲料等が挙げられる。これらの炭酸ガス含有飲料は２．０Ｇ．Ｖ．〜２．７Ｇ．Ｖ．のガスボリュームで充填され、４Ｋｇ／ｃｍ^２以上７Ｋｇ／ｃｍ^２以下の範囲となる加熱処理を行うものが好ましい。加熱処理としては、例えば６０℃〜７５℃の加熱殺菌が挙げられる。これ等の加熱処理により、缶内圧が上昇し、構成単位面の窪んだ部分の膨出がなされる。また他の不活性ガスと内容物の例としては、窒素ガス充填した果汁飲料、茶飲料、水等が挙げられる。
【００４３】
【実施例】
実施例１
板厚０．３２ｍｍのアルミ板を絞りしごき加工に付し（絞り比＝２．１３、しごき率＝６４．７％）、内容量３５０ｍｌ、半径ｒ３２．８８ｍｍ、高さＨ１２２．２０ｍｍ、胴部厚みｔ０．１１３ｍｍの有底缶胴を成形した。この有底缶胴に、常法により外面印刷をほどこした後、図８に示す方法で周状多面体パターンを刻設した。このパターンにおける構成単位面は四辺形であり、ｗ＝１５．９４ｍｍ、Ｌ＝１５．９４、Ｒ＝０．２ｍｍ及びｈ０＝０．９ｍｍとした。この有底缶胴にガスボリューム２．５Ｇ．Ｖ．の炭酸ガス入り酎ハイを充填し、易開封性口を有するアルミ製缶蓋を巻締めにより設け、酎ハイ詰め陽圧缶を得た。この酎ハイ詰め陽圧缶をパストライザーにて６５℃−１０分の加熱殺菌を行った後、常温まで冷却した。このときのｈ_１は約０．１ｍｍであった。図９は、この陽圧缶の缶内圧Ｐと構成単位面の窪んだ部分の最大深さｈの関係を示したものである。充填前に窪んだ部分の深い状態であったものが、加熱により缶内圧が上昇すると、図の曲線Ａに沿って窪みの深さが減少する。そして６５℃の殺菌中は缶内圧が約６．５Ｋｇ／ｃｍ^２まで上昇し、このときの窪みの深さｈは約０，０５ｍｍまで減少し、ほぼ滑らかな缶胴壁となる。ついに殺菌が終了し、缶の温度が下がり缶内圧が下がってくると、窪みの深さは今度は曲線Ｂに沿って変化する。すなわち窪みの深さは圧力が下がるにつれ、やや深くはなるもののその変化量はわずかであって、ｈ_１は０．１ｍｍ程度に留まり、ほぼ滑らかな多面体壁が保持される。開封前の陽圧缶の窪みの深さはｈ_１＝０．０９ｍｍであった（缶温２０℃、缶内圧２．０Ｋｇ／ｃｍ^２）。上記で得られた陽圧缶について、開封前の印刷図柄ゆがみ等の外観と、開封時の窪みの深い状態への復元性を評価し、その結果を表１に示した。上記陽圧缶を開封すると缶胴壁には窪みの深い多面体壁が現出し、開封後の窪みの深さはｈ_２＝０．７ｍｍであった。
【００４４】
実施例２、３
アルミ板の元板厚を０．３０ｍｍ、胴部厚みｔを０．１０５ｍｍとした以外は実施例１と同様にして酎ハイ詰め陽圧缶を製造し、開封前の外観と開封後の窪みの復元性の評価を行った。結果を表１に示す。
【００４５】
比較例１
板厚０．３０ｍｍのアルミ板を絞りしごき加工に付し（絞り比＝２．１３、しごき率＝６５．７％）、内容量３５０ｍｌ、半径ｒ３２．８８ｍｍ、高さＨ１２２．２０ｍｍ、胴部厚みｔ０．１０３ｍｍの有底缶胴を成形した。この有底缶胴に、常法により外面印刷をほどこした後、図８に示す方法で周状多面体パターンを刻設した。このパターンにおける構成単位面は四辺形であり、ｗ＝１８．７８ｍｍ、Ｌ＝１８．７８、Ｒ＝０．２ｍｍ及びｈ_０＝１．２３ｍｍとした。この有底缶胴にガスボリューム２．６Ｇ．Ｖ．のビールを充填し、易開封性口を有するアルミ製缶蓋を巻締めにより設け、ビール詰め陽圧缶を得た。これをウォーマーにて約４０℃に加熱した後、常温まで冷却した。このときのｈ_１は０，３５ｍｍであった。この缶を開封すると窪みの深い多面体壁が現出し、持ち易い缶となった。しかし開封前後での窪みの形状変化が少なく面白さに欠けるものであった。開封後の窪みの最大深さはｈ_２＝０．８ｍｍであった。結果を表１に示す。
【００４６】
比較例２
比較例１の缶に、内容物として実施例１と同じ炭酸ガス入り酎ハイを充填し６５℃で加熱殺菌した後、常温まで冷却した。このときの開封前の窪みの深さはｈ_１＝０．０６ｍｍであった。この缶を開封したところ、缶内圧がかからなくなっても缶胴の多面体壁は窪みの深い状態に戻らなかった。結果を表１に示す。
【００４７】
【表１】

【００４８】
（註）
▲１▼ 開封前の外観及び開封後の窪みの復元性は目視で評価した。評価基準は以下の通りである。
○：優れている
△：多少劣っている
×：劣っている
▲２▼ ｎは、缶胴周方向の構成単位面の数である。
【００４９】
【発明の効果】
本発明によれば、缶胴に特定の周状多面体を形成するのみで、缶詰の製造課程でかかる高い内圧を利用して、缶胴壁に形成した多面体壁の構成単位面の窪みが外方に膨らんで表面の凹凸が小さくなり独特の外観を与え印刷表示も見やすく装飾効果を高め、開缶すると凹凸が戻って意匠的な面白さを提供するとともに、缶が持ち易くなり、薄肉軽量であるが剛性が大きくなって飲用時に缶が潰れるなどの好ましくない変形が防止され、商品価値も高い。
【図面の簡単な説明】
【図１】四辺形を構成単位面とする周状多面体を設けた本発明の缶の側面図である。
【図２】図１に示した缶の縦断面図である。
【図３】図１に示した缶の水平縦断面図である。
【図４】図１の容器の側面に形成された多面体壁の構成単位面の平面図である。
【図５】図１に示した構成単位面の垂直断面図である。
【図６】図１とは異なる多面体壁を設けた缶の例を示す図である。
【図７】六角形の構成単位面とする多面体壁を設けた缶の例を示す図である。
【図８】缶胴部への多面体刻設の方法を説明する斜視図である。
【図９】缶内圧と構成単位面の窪みの最大深さとの関係を示す図である。
【符号の説明】
１構成単位面
２境界稜線
３交叉部
５構成単位面の凹部
６側壁部
７閉塞底部
８蓋体
１０缶[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a positive pressure can filled with a content containing an inert gas having a three-dimensional appearance and rigidity by arranging constituent unit surfaces having irregularities on the can body, and more specifically, the can body By forming a circumferential polyhedral wall, it is easy to have a three-dimensional effect and is filled with contents containing an inert gas. A can filled with contents containing an inert gas that forms a substantially smooth surface while displaying a wall, forming a polyhedral wall body to increase the rigidity of the can body, and recognizing printed displays during distribution It relates to a positive pressure can that does not impair the performance.
[0002]
[Prior art]
Conventionally, many proposals have been made to increase the added value by forming a polyhedral wall on the side wall of the can body.
For example, the proposals found in JP-A-53-143485 and JP-B-54-710 facilitate the bending and crushing of the can body by providing engravings and irregularities on the side wall of the can body. That's it. Further, a can having a polyhedral wall filled with an inert gas and a beverage is known, and the present inventor previously formed a polyhedral wall with irregularities on the can body as disclosed in Japanese Patent Application Laid-Open No. 8-26286. We proposed cans filled with beer and deformed by internal pressure.
[0003]
[Problems to be solved by the invention]
The previous proposal by the present inventor is that the can body panel bulges due to the internal pressure of the filled beer, and the can shape having a reduced depression depth of the polyhedral wall formed in advance becomes the original depression depth when the internal pressure is not applied by opening. It was a proposal to return to the shape of the large can body panel and enjoy beer foaming improvements and changes in can appearance. However, in the can proposed in Japanese Patent Laid-Open No. 8-26286, since beer is not heat-sterilized after filling and the internal pressure of the can at the time of canning is low, there is little change in the dent and shape at the time of filling and opening, and the effect of panel deformation There was a drawback that was small.
[0004]
In addition, conventional beverage cans, food cans, etc. are printed on the barrel, but they are printed when beads or polyhedral walls are formed on the barrel to increase rigidity and reduce the weight of the can. The display and design were distorted, making it difficult to see and the appearance and design were inferior. In addition, the can body is almost smooth during the distribution of canned food, and the printed display is easy to see.In addition, a polyhedral wall is placed to give a three-dimensional effect when drinking, making it easier to hold when holding by hand, increasing rigidity, and slipping. It is not known to prevent it.
[0005]
The object of the present invention is to use the high internal pressure applied in the manufacturing process of canned food, and the depressions of the constituent unit surface of the polyhedral wall formed on the can body wall swell outward and the surface irregularities become smaller and almost smooth. The polyhedron shape gives a unique appearance displayed on the can body and the printed display is easy to see.When the can is sealed, this shape is maintained even if the temperature of the can drops to room temperature and the internal pressure of the can drops. When the can is opened, the unevenness is restored to provide a fun design, and the can is easy to hold, thin and lightweight, but the rigidity is so great that it prevents excessive deformation such as crushing the can during drinking. It is in providing a pressure can and its manufacturing method.
[0006]
[Means for Solving the Problems]
  The present invention
“1. A can comprising a can body formed by squeezing and squeezing a metal plate, and a can lid or cap having a can bottom and an easy-open mouth provided at the upper end of the can body, At least a part of the structural unit surface has a boundary ridgeline where the structural unit surfaces are in contact with each other and a crossing part where the boundary ridgeline intersects, and the boundary ridgeline and the crossing part are relatively convex to the outside of the can compared to the structural unit surface. The structural unit surface has a recessed portion between the opposing crossing portions, and a circumferential polyhedral wall is formed in which the axial arrangement of can bodies adjacent to each other in the circumferential direction of the structural unit surface forms a phase difference. In the state in which the concave portion of the structural unit surface is filled with the contents and the internal pressure of the can is applied, it is expanded by the internal pressure, and the following formula (1),
          0mm <h₁≦ 0.2mm (1)
  (Where h₁Shows the maximum depth of the dent when the contents are filled and internal pressure is applied), and forms a substantially smooth and polyhedral wall display surface, and when opened, the following equation (2):
          0.5mm <h₂≦ 1.5mm (2)
  (Where h₂Indicates the maximum depth of the dent after opening)
A positive pressure can that forms a polyhedral wall consisting of structural unit surfaces with recessed partsAfter the positive pressure can is filled with the contents, the maximum value of the can internal pressure is 4 kg / cm. ² 7 kg / cm ² It is a can that performs heat treatment in the following rangeA positive pressure can with a polyhedral wall formed in the body.
  2.A can comprising a can body formed by squeezing and squeezing a metal plate, and a can lid or cap having a can bottom and an easily openable mouth provided at the upper end of the can body, and at least a part of the can body The unit ridge surface and the boundary ridgeline where the unit unit surfaces contact each other and the crossing portion where the boundary ridgeline intersects each other, and the boundary ridgeline and the crossover portion are relatively convex to the outside of the can compared to the unit unit surface. The structural unit surface has a recessed portion between opposing crossing portions, and a circumferential polyhedral wall is formed in which the axial arrangement of the can bodies adjacent in the circumferential direction of the structural unit surface forms a phase difference. In the state where the concave portion of the structural unit surface is filled with the contents and the internal pressure of the can is applied, the inflated portion expands due to the internal pressure, and the following formula (1),
          0mm <h ₁ ≤0.2mm      (1)
  (Where h ₁ Shows the maximum depth of the dent when the contents are filled and internal pressure is applied), and forms a substantially smooth and polyhedral wall display surface, and when opened, the following equation (2):
          0.5mm <h ₂ ≦ 1.5mm  (2)
  (Where h ₂ Indicates the maximum depth of the dent after opening)
A positive pressure can that forms a polyhedral wall composed of a structural unit surface having a recessed portion that satisfies the above-mentioned conditions, wherein the positive pressure can is filled with nitrogen gas. Positive pressure can formed in
  3.SaidcanTrunkofSaidThe recessed part of the structural unit surface is the following formula (3)
          0.8mm ≦ h₀≦ 1.7mm (3)
  (Where h₀Indicates the maximum depth of the recess before filling the contents)
Satisfy the claim1 or 2The positive pressure can which formed the polyhedron wall described in 1 in the trunk | drum.
  4). The positive pressure can is a can that is filled with a carbon dioxide-containing beverage as a content and is heat-sterilized after filling.1A positive pressure can in which the described polyhedral wall is formed in the body.
  5. An inner die having a surface formed with a projection corresponding to the top of the polyhedron, a protrusion corresponding to the boundary ridgeline, and a concave surface corresponding to the concave concave surface of the structural unit surface on the can body formed by drawing and ironing a metal plate And insert the outer die having a surface corresponding to the crossing portion of the polyhedron and the boundary ridge line and the surface on which the convex unit array corresponding to the concave concave surface of the structural unit surface is formed, and sandwich the can body part In the can where the inner and outer molds are rotated and pressed to form a polyhedral wall in the can body, the contents containing inert gas are filled and sealed, and the maximum value of the can internal pressure is 4 kg / cm.²7 kg / cm²The polyhedral wall is formed into a body part by performing a heat treatment in the following range and inflating the recessed portion of the structural unit surface outward to form a substantially smooth surface displaying the polyhedral wall on the body surface. Manufacturing method of the formed positive pressure can. "
About.
[0007]
In the present invention, it is important from the viewpoint of improving the external appearance characteristics of the can and improving the rigidity and rigidity that the recessed portion of the structural unit surface satisfies the following formulas (1) and (2). is there. That is, in the state where the concave portion of the structural unit surface is filled with the contents and the internal pressure of the can is applied, the following expression (1)
0mm <h₁≦ 0.2mm (1)
(Where h₁Indicates the maximum depth of the recess when the contents are filled and internal pressure is applied)
More preferably 0 mm <h₁Forming a substantially smooth and polyhedral wall display surface satisfying ≦ 0.15 mm has an effect of easily recognizing the printed display of the can body, giving a unique appearance, and being excellent in design. Moreover, since the unevenness | corrugation of the surface of a can body is small, it is suitable also for conveyance of a can. h₁When the thickness is 0 mm or less, the restoration property of the panel to a state where the depression at the time of opening is large becomes worse,₁If it is larger than 0.2 mm, the amount of change in the depression at the time of opening is reduced, the shape change is inferior, the printing before opening becomes difficult to see, and the transportability is inferior. On the other hand, the recessed part of the structural unit surface is the following formula (2) after opening,
0.5mm <h₂≦ 1.5mm (2)
(Where h₂Indicates the maximum depth of the dent after opening)
More preferably 0.6 mm <h₂By forming a polyhedral wall composed of structural unit surfaces having a recessed portion that satisfies ≦ 1.0 mm, the difference between h1 and h2 increases, and the amount of change in the depression before and after opening increases, resulting in a change in shape. There is an effect that it is interesting. It is also excellent in that a polyhedral wall with a depression is provided for drinking to give a three-dimensional effect, to make it easier to hold when held by hand, to increase rigidity, and to prevent slipping. h₂Is less than 0.5 mm, the amount of change in the depressions before and after opening is small, and the shape change is inferior. h₂If the thickness exceeds 1.5 mm, it is difficult to form a polyhedral pattern, and the appearance of the printed display after opening is inferior.
[0008]
Moreover, the recessed part of the said structural unit surface is following Formula (3).
0.8mm ≦ h₀≦ 1.7mm (3)
(Where h₀Indicates the maximum depth of the recess before filling the contents)
More preferably, 0.8 mm ≦ h₀It is preferable that ≦ 1.1 mm is satisfied. h₀Is less than 0.8 mm, the depth h of the dent after opening₂Tends to be small, and the interest in shape change tends to be reduced. h₀If the thickness exceeds 1.7 mm, it is difficult to form a polyhedral pattern, and the appearance of the printed display after opening is inferior.
[0009]
In addition, the positive pressure can of the present invention has a maximum value of 4 kg / cm after filling the contents.²7 kg / cm²Or less, more preferably 4.5 kg / cm²6.5 kg / cm or more²It is preferable to perform the heat treatment within the following range. When an internal pressure in this range is applied, the depression of the structural unit surface formed in the can body bulges outward and the unevenness is reduced, so that a substantially smooth polyhedral shape appears. The maximum pressure inside the can is 4Kg / cm²If it is less than that, the amount of protrusion of the dent is small and it is difficult to obtain a smooth shape. On the other hand, the maximum value of the can internal pressure is 7 kg / cm.²If it exceeds 1, buckling of the bottom of the can occurs, which may cause a problem in the pressure resistance of the can. After filling the contents, the maximum value of the internal pressure of the can is 4 kg / cm2 by heat treatment.²7 kg / cm²When the following range is reached, the depression of the structural unit surface formed on the can body bulges outward and the irregularities become smaller and a substantially smooth polyhedral shape is expressed, but once this panel is inflated, the heating is finished and the can The temperature drops and the internal pressure of the can is 1Kg / cm²Even if it is lowered to the extent, the panel remains inflated, and the dent of the structural unit surface does not return to the original deep state, and the shallow state of the dent remains almost smooth. When the internal pressure is released at once, it is restored to the deep state of the depression.
[0010]
In addition, the positive pressure can of the present invention is preferably filled with a carbon dioxide-containing beverage as a content and heat sterilized after filling, because a high can internal pressure can be obtained in the production process, so that the can body panel is easily projected. Furthermore, the positive pressure can of the present invention may be filled with nitrogen gas. In this case, even if the contents themselves do not contain an inert gas such as carbon dioxide, a high can internal pressure is obtained by the pressure of nitrogen gas, so that the panel can be deformed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, by utilizing the paneling deformation of the circumferential polyhedral wall formed in the can body, the shape of the body of the positive pressure can filled with the inert gas and the content and the internal pressure is applied to the sealed state after filling It changes at the time of opening, draws attention by changing the shape and expresses a three-dimensional effect, improving ease of holding and rigidity. That is, the circumferential polyhedral wall has a large number of recessed portions toward the inside of the container, but the can constituent material is an aluminum plate or a steel plate, and the barrel thickness is 0.080 to Since the thickness is reduced to 0.150 mm, the recessed portion is deformed outward by filling the contents containing inert gas and the subsequent increase in the internal pressure of the can by heat sterilization. The depth of the can body decreases, and the can body as a whole becomes an expanded shape, and is maintained in this state even if the temperature drops to room temperature after heating. In this state, when the easy-open mouth formed on the container lid is opened, a large number of recessed portions of the can body that swells outward and is in a smooth state are deep in the recesses before filling the contents. Return to. By this return, in the case of a beverage whose content contains an inert gas such as carbon dioxide, vaporization of the inert gas contained in the beverage is promoted. In this way, the can body is actively deformed from a smooth surface to a deep dent, and the three-dimensional effect of the can body is changed to enjoy the shape change and attract attention, and the polyhedral wall appears at the time of drinking. It can be released to improve ease and rigidity. For example, if the contents are a beverage, that is, a beverage can, it is important to make it easy to hold the beverage as it is because it is slippery due to condensation, even if the beverage is drunk as it is or poured into a cup etc. In addition, the can must be prevented from being deformed and spilled. On the other hand, before opening, it is important to reduce the depression of the polyhedral wall to make the printed display easier to see and to improve the transportability.
[0012]
The positive pressure can according to the present invention is a positive pressure can filled with an inert gas and having a high can internal pressure in the manufacturing process by heating after sealing, and the maximum value of the can internal pressure is 3.5 kg / cm.²A positive pressure can having a higher internal pressure than that of beer is preferred. At this high internal pressure, the can body is almost smooth and the polyhedral wall is exposed by filling and subsequent heating, and this state is maintained even after the heating returns to room temperature and the can internal pressure decreases. Therefore, the shape of the can used in the present invention is greatly deformed at the time of filling and after opening, and the rigidity, grip properties and the like are improved.
[0013]
The circumferential polyhedron wall formed in the can body portion of the can used in the present invention will be described. The circumferential polyhedron wall is composed of a structural unit surface, a boundary ridge line where the structural unit surfaces are in contact with each other, and a crossing portion where the boundary ridge lines intersect each other. Consists of. The structural unit surface is a unit surface that repeatedly appears in the axial direction (container height direction) and / or circumferential direction of the circumferential polyhedral wall, and this surface is a bent surface, a refracting surface, or an assembly of a plurality of surfaces. is there. The structural unit surfaces are in contact with each other in the axial direction and the circumferential direction via boundary ridge lines, and a crossing portion, that is, a vertex exists at a position where the boundary ridge lines intersect with each other.
[0014]
The can used in the present invention is such that the boundary ridge line and the crossing portion protrude relative to the outer side of the container relative to the constituent unit surface, and at least a part of the constituent unit surface is recessed inside the container so as to compensate for this. It is also an important feature that the arrangement in the container axial direction adjacent to the circumferential direction of the structural unit surface is not an arrangement having a phase difference.
[0015]
In the above-described arrangement of the circumferential polyhedral wall, an arrangement in which convex portions formed of boundary ridge lines and crossing portions and concave portions formed of at least a part of the constituent unit surface are always alternated in any direction in the circumferential direction and the axial direction. That is, the arrangement is repeated such that the convex portion-the concave portion-the convex portion-the concave portion. In addition, since these convex portions and concave portions are formed by meshing the structural unit surfaces with no gaps, the can body wall is extremely thin, but the rigidity is large and the deformation of the vessel wall is prevented. The resistance is also large, and the internal pressure due to filling with inert gas and beverage and the decompression due to opening of the can, the deformation of the vessel wall (especially the recess) does not impair the commercial value of the can, but rather it is a good deformation that increases the commercial value, In addition, since the deformation of the concave portion occurs over the entire circumferential polyhedral wall, the can body portion becomes a smooth surface displaying the polyhedral wall due to internal pressure, and irregularities that are easy to hold are formed when the can is opened.
[0016]
This will be specifically described with reference to the drawings. FIG. 1 shows an example of the basic structure and shape of a can used in the present invention. 1 is a side view of the can of the present invention, FIG. 2 is a partial side sectional view of the can of FIG. 1 cut along the line AA ', and FIG. 3 is a horizontal section of the can of FIG. 1 cut along the line BB'. FIG. The can 10 is formed by squeezing and squeezing an aluminum plate, and includes a side wall portion 6 and a closed bottom portion 7 of an upper opening, and a lid body 8 provided at the upper end by winding. The side wall 6 is formed with a polyhedron wall in a circumferential shape, and the polyhedron wall has a structural unit surface 1, a boundary ridge line 2 where the structural unit surfaces contact each other, and a crossing portion 3 where the boundary ridge lines intersect each other, The boundary ridge line 2 and the crossing portion 3 are relatively convex toward the outside of the container as compared to the structural unit surface, and at least a part 5 of the structural unit surface 1 is relatively concave toward the inside of the container. Moreover, in this polyhedral wall, the adjacent container axial direction arrangement | sequence of the structural unit surface 1 becomes the arrangement | sequence which made the phase difference.
[0017]
FIG. 4 is an explanatory diagram of a structural unit surface, and shows one structural unit surface in a polyhedral wall formed on the container body,
FIG. 5 is a diagram showing a vertical cross section of the central portion of the structural unit surface. In the structural unit surface 1 of FIG. 1, the container axial arrangement adjacent to the circumferential direction is arranged with a phase difference of exactly ½. Each side ab, bc, cd, da in FIG. 4 is a side corresponding to the boundary ridge line 2 formed on the side surface of the container, and vertices a, b, c, d that are convex outward correspond to the crossover part 3. .
[0018]
The upper vertex a and the lower vertex c are located on the circumferential surface having the same diameter, and the left vertex b and the right vertex d are located on the circumferential surface having the same diameter. When the arrangement has a phase difference of ½, all the vertices are located on the circumferential surface of the same diameter, and as shown in FIG. 3, the radius in the container body corresponding to these vertices is the maximum radius. r. On the other hand, each ridge line ab, bc, cd, da protrudes most radially outward at a, b, c, d which is also an intersection, but the distance from the central axis of the container as it goes between the intersection and the intersection, that is, The diameter decreases. The diameter s of the midpoint of the circumferential diagonal bd is smaller than r, and in FIG.
In FIG. 4, vertices a and b of the structural unit surface are arranged on the same straight line along the axis of the container body, and vertices b and C are arranged on the same curve on the same surface of the container body.
The diagonal lines a and c are positioned radially outward from the diagonal line bc, and the quadrangle abcd is a smoothly curved surface with the diagonal line recessed most radially inward.
[0019]
In FIG. 4, the rhombus dimensions as the constituent unit surface are such that the length of the circumferential diagonal line bd is w and the height of the axial diagonal line ac is L, and w and L are the maximum circumferential width of the constituent unit surface, respectively. And the maximum length in the axial direction. Compared with the length ac (height L) of the diagonal in the axial direction, the length of the actual ac cross section on the structural unit surface is long, and this ac cross section is a curved curve that is smoothly recessed inside the container. The length of the ac cross section on the structural unit surface decreases as the radius of curvature R of the recess increases.
[0020]
Furthermore, in each structural unit surface, the length (w) of the circumferential diagonal line bd may differ from the length in the bd cross section on the actual structural unit surface. For example, in FIG. 3, the circumferential diagonal line bd and the bd cross section on the actual structural unit surface coincide with each other, and their lengths are equal, but the midpoint of the side ac in this cross section is from the position of the circumferential diagonal line bd. May be located in the radially outward direction or in the radially inward direction.
[0021]
For example, in the example shown in FIGS. 3 and 5, the ac section is smoothly curved and the bc section is substantially straight. However, in FIG. 6 showing another specific example, both the ac section and the bd section are included. Since it is curved so as to be recessed smoothly, the length increases.
[0022]
In the can used in the present invention, the above-described circumferential polyhedral wall is arranged in the vicinity of the opening and the bottom of the can body, that is, the entire surface of the body except for the upper and lower portions of the body, but at least 25 of the can body. % Or more, preferably 60% or more. More preferably, it is formed at 80% to 25%. When the ratio of the circumferential polyhedral wall occupying the can body is smaller than the above range, the paneling deformation at the time of opening the can is reduced, the change in shape due to the polyhedral wall exposed to the can body is reduced, and the three-dimensional effect and The effect of rigidity and ease of holding deteriorates.
It is preferable that the polyhedral wall is not disposed on the upper and lower portions of the can body because the upper and lower portions of the body portion are held by a jig in the can manufacturing process and the transferring process.
[0023]
Moreover, it is preferable that the number of the structural unit surfaces which exist in the circumference | surroundings of a container trunk | drum is at least 4 or more. That is, if the number of the structural unit surfaces is less than 4, the effect of paneling deformation at the time of opening the can is reduced, and when the polyhedral wall is formed on the body part, the bending on the body part surface becomes severe. The corrosion resistance of the coating film is significantly reduced and the appearance is also deteriorated. The pattern of the polyhedral wall formed on the cutting body is monotonous, and the rigidity and the ease of holding the can are not improved. Thus, the effect by the shape change of a polyhedral wall becomes small.
[0024]
Moreover, generally speaking, the maximum length L in the can body axial direction and the maximum length w in the can circumferential direction of the structural unit surface are preferably in the range of 1 to 3 cm, particularly 1.5 to 2.5 cm, respectively. It is. When these lengths L and w are smaller than the above range, the paneling deformation at the time of opening the can described above is difficult to occur, and when larger than the above range, the effect of the paneling deformation is reduced, the three-dimensional effect, Stiffness and ease of holding may not be improved.
[0025]
In the present invention, the paneling deformation at the time of opening the can described above uses a metal plate such as aluminum or steel as the can material metal, and forms a polyhedral wall in a thin can body formed by drawing and squeezing the metal plate. In order to promote the effect of the positive pressure can filled with an inert gas due to the paneling deformation, the maximum depth of the recessed portion of the structural unit surface before opening the positive pressure can and the positive pressure It is important to satisfy the following relationship with the maximum depth of the recessed portion of the structural unit surface after opening the can.
[0026]
That is, in the vertical sectional view of the central portion of the structural unit surface shown in FIG. 5, the maximum depth of the recessed portion of the structural unit surface before opening of the positive pressure can filled with the inert gas and the contents is h.₁, H is the maximum depth of the recessed portion of the structural unit surface in the can after opening₂Are both within the range defined by the above formulas (1) and (2), that is,
0mm <h₁≦ 0.2mm (1)
And 0.5mm <h₂≦ 1.5mm (2)
It is important to be in More preferably, each 0 mm <h₁≦ 0.15mm, 0.6mm <h₂≦ 1.0 mm is preferable.
[0027]
This h₁And h₂The difference corresponds to the degree of deformation of the can body when the can is opened. For example, h₁Is greater than the above range or h₂Is smaller than the above range and h₂And h₁When the difference is small, the return of the hollow portion of the body wall when opening the can becomes small, and the effect of paneling deformation of the can body becomes small. H₁If it is smaller than the above range, the expansion of the can body due to the filling of the inert gas becomes too large, and the return deformation of the recess of the panel at the time of opening hardly occurs. H₁When the value is larger than the above range, it becomes difficult to form a polyhedral pattern. That is, h within the above range₁, H₂If there is, the effect by paneling deformation is not only extremely high, but also in a state of filling and sealing with inert gas and contents, a unique three-dimensional feeling and aesthetics are imparted to a positive pressure can filled with these. The product value is extremely high. Usually, if there is a deeply refracted portion on the side wall of the can body, this portion is likely to be shaded, making it difficult to see the printed image on the surface, and the decorative effect is reduced and the commercial value is impaired. On the other hand, in the polyhedron pattern formed according to the present invention, the structural unit surfaces are regularly combined, and in the filled state of the inert gas and the contents, the structural unit surfaces are smoothly recessed in a state close to a very flat surface. Therefore, the product value is extremely high.
[0028]
Further, in the positive pressure can according to the present invention, the maximum depth of the recessed portion of the structural unit surface before filling with the inert gas or the content is h.₀When h₀Is within the range defined by the formula (3), that is, 0.8 mm ≦ h0 ≦ 1.7 mm, more preferably 0.8 mm ≦ h.₀It is desirable that the range satisfies ≦ 1.1 mm. This h₀Also indirectly affects the degree of deformation of the can body when the can is opened, h₀Is less than 0.8 mm, the depth h of the dent after opening₂Tends to be small, and the interest in shape change tends to be reduced. h₀If the thickness exceeds 1.7 mm, it is difficult to form a polyhedral pattern, and the printed display appearance before opening is inferior.
[0029]
In order to cause the deformation satisfying the above-described formulas (1) and (2), it is preferable that the thickness of the can barrel side wall 6 is 0.150 mm or less, particularly 0.080 to 0.150 mm. The radius of curvature R of the recessed portion of the structural unit surface formed in the state before filling with the contents containing the inert gas
(Mm) is the following formula (4):
0.1 ≦ R ≦ 0.5 (4)
Especially the following formula (5)
0.2 ≦ R ≦ 0.4 (5)
It is desirable to form a circumferential polyhedral wall on the can body so as to satisfy the above. That is, when the thickness of the can barrel side wall 6 is thicker than the above range, the paneling deformation described above may not occur effectively. Further, if the curvature R of the recessed portion is smaller than the range defined by the above formula, a fold at the time of processing is formed in the recess, so that not only the appearance of the can is impaired, but also the side wall is formed at the fold. If deformation such as folding easily occurs and the curvature R is larger than the range defined by the above equation, the depth of the recess becomes shallow and the local deformation low efficacy becomes small. It is difficult to cause an appropriate deformation to satisfy (2).
[0030]
In addition, in the can used in the present invention, the structural unit surface is not limited to a quadrilateral, and is particularly preferably a rhombus, but other polygons can of course be used, for example, a hexagon. Can do. FIG. 7 shows an example in which the structural unit surface is a hexagon. Even in this case, the basic configuration of the polyhedron is the same as that described above.
[0031]
The can used in the present invention uses an aluminum plate or a steel plate as a metal material, forms a can body having a thin side wall portion by drawing and ironing the metal plate, and engraves a circumferential polyhedron on the can body. Then, after filling the beverage, it is manufactured by providing a can lid having an easily openable mouth by winding and tightening.
[0032]
In addition to so-called pure aluminum, an aluminum alloy can be used as the metal material aluminum. In particular, aluminum alloys excellent in corrosion resistance and workability are Mn: 0.2 to 1.5% by weight, Mg: 0.8 to 5% by weight, Zn: 0.25 to 0.3% by weight, Cu: It has a composition of 0.15 to 0.25% by weight and the balance is Al. These aluminum or aluminum alloys have a chromium content of 3 to 300 mg / m in terms of metal chromium.²It is desirable that chromic acid / phosphoric acid treatment is performed. As the steel, it is possible to use a cold-rolled steel sheet or foil subjected to one or more surface treatments such as tin plating, nickel plating, electrolytic chromic acid treatment, and chromic acid treatment.
[0033]
Forming a can body using the above metal material, the base plate is squeezed and subjected to a single-stage or multi-stage drawing process between a die and a punch to form a bottomless can body that has no side face. This is performed by performing one-step or multi-step ironing between the iron punch and the die. The drawing and ironing process is preferably performed so that the thickness of the body wall to be finally thinned is within the above-described range, that is, 0.150 mm or less, particularly 0.080 to 0.150 mm. In general, the total drawing ratio should be in the range of 1.8 to 2.5, particularly 2.0 to 2.3, and the following formula:
R₁= 100 × (t₀-T₁) / T₀
Where t₀Wall thickness before laddering, t₁Ironing rate expressed by the wall thickness after ironing (R₁) Is preferably 50 to 80%, particularly 60 to 70%.
[0034]
Formation of the circumferential polyhedron on the can body body before attaching the lid formed as described above is performed by embossing the can body body with an inner mold and an outer mold to form the polyhedron. The inner mold to be used has protrusions corresponding to the apexes and ridgelines of the polyhedron on the surface, while the outer mold to be used has protrusions corresponding to the valleys of the polyhedron on the surface. The polyhedron is formed by engaging the mold and the outer mold through the container body.
[0035]
FIG. 8 is an explanatory view showing a method of engraving a polyhedron in the can body body, but is shown with a part of the can body body cut away for easy understanding. In this example, the case where the structural unit surface is a quadrilateral is shown. However, even in the case where the structural unit surface is other than a quadrilateral, there is no difference in principle. The can body body 10 is rotated while being sandwiched between the inner mold 11 and the outer mold 12. On the surface of the inner mold 11, a protrusion 13 corresponding to the vertex of the polyhedron, a protrusion 14 corresponding to the boundary ridge line, and a recessed concave surface 15 corresponding to the structural unit surface are formed. On the other hand, on the surface of the outer mold 12, grooves 16 corresponding to the intersections and boundary ridgelines of the polyhedron and convex surfaces 17 corresponding to the structural unit surfaces are formed.
[0036]
The inner mold 11 and the outer mold 12 are meshed with each other through the can body 10 and rotated at a synchronized speed, whereby the polyhedron is engraved on the container body. Note that when the mesh is partially disengaged during rotation, the inner mold or the outer rotation shaft may slightly move up and down.
[0037]
In the specific example shown in FIG. 8, the inner mold 11 and the outer mold 12 have a diameter smaller than that of the can body portion 10, but the circumferential direction of the basic surface constituent units on the surfaces of the inner mold 11 and the outer mold 12. Since the number of arrangements is one or more less than that around the body of the can body, since the arrangement overlaps at the start point and end point of the arrangement of the constituent unit surfaces, the unevenness becomes clear . By separating the inner mold 11 and the outer mold 12, the polyhedral engraved can body can be easily taken out.
By overlapping, the start point portion and the end point portion are also reliably formed, so that a joint portion without unevenness does not occur.
[0038]
The can used in the present invention can be provided with a protective coating of resin on the metal plate or can body at any stage prior to the polyhedron carving or after the polyhedron pattern carving. The protective coating is formed by providing a protective coating or by laminating a thermoplastic resin film.
[0039]
The protective coating may be any protective coating composed of thermosetting and thermoplastic resins: modified epoxy coatings such as phenol-epoxy coatings and amino-epoxy coatings: vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate Partially saponified polymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, epoxy-modified, epoxyamino-modified or epoxyphenol-modified vinyl or modified vinyl paint such as vinyl paint: acrylic resin-based paint: styrene-butadiene A single or a combination of two or more synthetic rubber-based paints such as a copolymer is used.
[0040]
These paints are in the form of enamel or lacquer organic solvent solutions, or in the form of aqueous dispersions or aqueous solutions, such as roller coating, spray coating, dip coating, electrostatic coating, electrophoretic coating, etc. Apply to the material. Of course, when the resin paint is thermosetting, the paint is baked if necessary. From the viewpoint of corrosion resistance and workability, the protective coating generally desirably has a thickness of 2 to 30 μm, particularly 3 to 20 μm in a dry state. Moreover, in order to improve workability, various lubricants can be contained in the coating film.
[0041]
The thermoplastic resin film used for laminating includes polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic ester copolymer, ionomer and other olefin resin films, polyethylene terephthalate, polybutylene. Polyester films such as terephthalate and ethylene terephthalate / isophthalate copolymer: Polyamide films such as nylon 6,

nylon

6,6, nylon 11, and nylon 12: polyvinyl chloride film: polyvinylidene chloride film, and the like. These films may be unstretched or biaxially stretched. The thickness is desirably in the range of generally 3 to 50 μm, particularly 5 to 40 μm. Lamination of film to metal material is performed by heat fusion, dry lamination, extrusion coating, etc. If the adhesion between film and metal foil is poor (heat fusion), for example, urethane Adhesives, epoxy adhesives, acid-modified olefin resin adhesives, copolyamide adhesives, and copolyester adhesives can be interposed.
[0042]
The lid is made of the same aluminum as the can, and the shape of the lid is conventionally known. For example, an easy-open mouth is formed by a score, and an easy-open mouth is formed by a tab or the like. Opening is performed. Moreover, as a cap, the thing made from aluminum and a plastics can be used conveniently, A shape etc. may be a conventionally well-known thing. In the positive pressure can filled with the inert gas and the contents thus formed, the hollow portion of the structural unit surface of the circumferential polyhedron is compared with that before filling with the inert gas due to the internal pressure of the filled inert gas. The can is expanded and deformed outward, but the deformed portion is paneled and restored to the state before filling with the inert gas and the contents by opening the can.
Examples of the contents filled with the inert gas in the present invention include carbonated drinks, shochu containing carbon dioxide, alcoholic drinks such as strawberry high, spirits, and liqueurs. These carbon dioxide-containing beverages are 2.0G. V. ~ 2.7G. V. 4Kg / cm with a gas volume of²7 kg / cm²What performs the heat processing used as the following ranges is preferable. Examples of the heat treatment include heat sterilization at 60 ° C. to 75 ° C., for example. By these heat treatments, the internal pressure of the can is increased, and the recessed portion of the structural unit surface is bulged. Examples of other inert gases and contents include fruit juices filled with nitrogen gas, tea beverages, and water.
[0043]
【Example】
Example 1
An aluminum plate having a plate thickness of 0.32 mm is drawn and ironed (drawing ratio = 2.13, ironing rate = 64.7%), content 350 ml, radius r32.88 mm, height H122.20 mm, trunk thickness A bottomed can body having a t of 0.113 mm was formed. After the outer surface was printed on the bottomed can body by a conventional method, a circumferential polyhedral pattern was engraved by the method shown in FIG. The structural unit surface in this pattern was a quadrangle, and w = 15.94 mm, L = 15.94, R = 0.2 mm, and h0 = 0.9 mm. A gas volume of 2.5G. V. An aluminum can lid filled with a carbon dioxide gas containing cocoon gas and having an easy-open mouth was provided by tightening to obtain a positive pressure can filled with cocoon gas. The high pressure cans filled with straw were sterilized by heating at 65 ° C. for 10 minutes with a paste riser, and then cooled to room temperature. H at this time₁Was about 0.1 mm. FIG. 9 shows the relationship between the can internal pressure P of this positive pressure can and the maximum depth h of the recessed portion of the structural unit surface. When the internal pressure of the can rises due to heating in the deep state of the recessed portion before filling, the depth of the recessed portion decreases along the curve A in the figure. During the sterilization at 65 ° C., the internal pressure of the can is about 6.5 kg / cm.²The depth h of the depression at this time is reduced to about 0.05 mm, resulting in a substantially smooth can body wall. When the sterilization is finally finished and the temperature of the can decreases and the internal pressure of the can decreases, the depth of the recess changes along the curve B this time. In other words, the depth of the depression becomes slightly deeper as the pressure decreases, but the amount of change is slight, and h₁Remains on the order of 0.1 mm, and a substantially smooth polyhedral wall is retained. The depth of the depression of the positive pressure can before opening is h₁= 0.09 mm (can temperature 20 ° C., can internal pressure 2.0 kg / cm²). The positive pressure can obtained above was evaluated for its appearance such as printed pattern distortion before opening, and the ability to restore a deep dent when opened, and the results are shown in Table 1. When the above positive pressure can is opened, a deep polyhedral wall appears on the can body wall, and the depth of the depression after opening is h.₂= 0.7 mm.
[0044]
Examples 2 and 3
Except for the original thickness of the aluminum plate being 0.30 mm and the body thickness t being 0.105 mm, a positive high pressure can was produced in the same manner as in Example 1, and the appearance before opening and the depression after opening Restorability was evaluated. The results are shown in Table 1.
[0045]
Comparative Example 1
An aluminum plate having a thickness of 0.30 mm is drawn and ironed (drawing ratio = 2.13, ironing rate = 65.7%), content 350 ml, radius r32.88 mm, height H122.20 mm, body thickness A bottomed can body having a t of 0.103 mm was formed. After the outer surface was printed on the bottomed can body by a conventional method, a circumferential polyhedral pattern was engraved by the method shown in FIG. The structural unit surface in this pattern is a quadrilateral, w = 18.78 mm, L = 18.78, R = 0.2 mm and h.₀= 1.23 mm. A gas volume of 2.6G. V. A beer-packed positive pressure can was obtained by winding an aluminum can lid having an easy-opening mouth. After heating this to about 40 degreeC with the warmer, it cooled to normal temperature. H at this time₁Was 0.35 mm. When this can was opened, a deep polyhedral wall appeared, making it easy to hold. However, there was little change in the shape of the dent before and after opening, and it was not interesting. The maximum depth of the dent after opening is h₂= 0.8 mm. The results are shown in Table 1.
[0046]
Comparative Example 2
The can of Comparative Example 1 was filled with the same carbon dioxide-filled salmon high as in Example 1 and sterilized by heating at 65 ° C., and then cooled to room temperature. The depth of the dent before opening at this time is h₁= 0.06 mm. When the can was opened, the polyhedral wall of the can body did not return to the deep state of the depression even when the internal pressure of the can disappeared. The results are shown in Table 1.
[0047]
[Table 1]

[0048]
(註)
(1) The appearance before opening and the restorability of the depression after opening were evaluated visually. The evaluation criteria are as follows.
○: Excellent
Δ: Somewhat inferior
×: Inferior
(2) n is the number of structural unit surfaces in the circumferential direction of the can body.
[0049]
【The invention's effect】
According to the present invention, only by forming a specific circumferential polyhedron on the can body, the depression of the unit surface of the polyhedron wall formed on the can body wall is outward using the high internal pressure applied in the can manufacturing process. The surface is uneven and the surface unevenness is reduced, giving it a unique appearance and easy-to-read print display, enhancing the decorative effect.When the can is opened, the unevenness is restored and the design is fun, and the can is easy to hold and is thin and lightweight. However, since the rigidity is increased, undesirable deformation such as crushing of the can during drinking is prevented, and the commercial value is high.
[Brief description of the drawings]
FIG. 1 is a side view of a can of the present invention provided with a circumferential polyhedron having a quadrilateral as a structural unit surface.
FIG. 2 is a longitudinal sectional view of the can shown in FIG.
FIG. 3 is a horizontal longitudinal sectional view of the can shown in FIG.
4 is a plan view of a structural unit surface of a polyhedral wall formed on the side surface of the container of FIG. 1; FIG.
5 is a vertical sectional view of the structural unit surface shown in FIG. 1. FIG.
6 is a view showing an example of a can provided with a polyhedral wall different from FIG. 1; FIG.
FIG. 7 is a diagram showing an example of a can provided with a polyhedral wall as a hexagonal structural unit surface.
FIG. 8 is a perspective view for explaining a method of engraving a polyhedron in a can body part.
FIG. 9 is a diagram showing the relationship between the internal pressure of the can and the maximum depth of the depression on the structural unit surface.
[Explanation of symbols]
1 Structural unit surface
2 border ridgeline
3 Crossing
5 Concavities on the unit surface
6 Side wall
7 Blocking bottom
8 Lid
10 cans

Claims

A can comprising a can body formed by squeezing and squeezing a metal plate, and a can lid or cap having a can bottom and an easily openable mouth provided at the upper end of the can body, and at least a part of the can body The unit ridge surface and the boundary ridgeline where the unit unit surfaces contact each other and the crossing portion where the boundary ridgeline intersects each other, and the boundary ridgeline and the crossover portion are relatively convex to the outside of the can compared to the unit unit surface. The structural unit surface has a recessed portion between opposing crossing portions, and a circumferential polyhedral wall is formed in which the axial arrangement of the can bodies adjacent in the circumferential direction of the structural unit surface forms a phase difference. In the state where the concave portion of the structural unit surface is filled with the contents and the internal pressure of the can is applied, the inflated portion expands due to the internal pressure, and the following formula (1),
0 mm <h ₁ ≦ 0.2 mm (1)
(Where h ₁ indicates the maximum depth of the dent when the contents are filled and the internal pressure is applied) is satisfied, forms a substantially smooth and polyhedral wall display surface, and opens the following formula ( 2),
0.5 mm <h ₂ ≦ 1.5 mm (2)
(Wherein h ₂ indicates the maximum depth of the depression after opening)
A positive pressure can that forms a polyhedral wall composed of structural unit surfaces having recessed portions, and after the positive pressure can is filled with the contents, the maximum value of the can internal pressure is 4 kg / cm ² or more and 7 kg / A positive pressure can in which a polyhedral wall is formed in a body portion, wherein the can is subjected to heat treatment in a range of cm ² or less .

A can comprising a can body formed by squeezing and squeezing a metal plate, and a can lid or cap having a can bottom and an easily openable mouth provided at the upper end of the can body, and at least a part of the can body The unit ridge surface and the boundary ridgeline where the unit unit surfaces contact each other and the crossing portion where the boundary ridgeline intersects each other, and the boundary ridgeline and the crossover portion are relatively convex to the outside of the can compared to the unit unit surface. The structural unit surface has a recessed portion between opposing crossing portions, and a circumferential polyhedral wall is formed in which the axial arrangement of the can bodies adjacent in the circumferential direction of the structural unit surface forms a phase difference. In the state where the concave portion of the structural unit surface is filled with the contents and the internal pressure of the can is applied, the inflated portion expands due to the internal pressure, and the following formula (1),
0 mm <h ₁ ≦ 0.2 mm (1)
(Where h ₁ indicates the maximum depth of the dent when the contents are filled and the internal pressure is applied) is satisfied, forms a substantially smooth and polyhedral wall display surface, and opens the following formula ( 2),
0.5 mm <h ₂ ≦ 1.5 mm (2)
(Wherein h ₂ indicates the maximum depth of the depression after opening)
Satisfying, a positive pressure can be formed polyhedral wall comprising a structural unit face having a recessed portion, the positive pressure can is, the body portion polyhedral wall, characterized in that filled with nitrogen gas Positive pressure can formed in

Wherein the structural unit recessed with surface portions of the can body is the following formula (3)
0.8 mm ≦ h ₀ ≦ 1.7 mm (3)
(Where h ₀ indicates the maximum depth of the recess before filling the contents)
The positive pressure can according to claim 1 or 2 , wherein a polyhedral wall is formed in the body portion.

The positive pressure can according to claim 1, wherein the positive pressure can is a can filled with a carbon dioxide-containing beverage as a content and sterilized by heating after filling.

An inner die having a surface formed with a projection corresponding to the top of the polyhedron, a protrusion corresponding to the boundary ridgeline, and a concave surface corresponding to the concave concave surface of the structural unit surface on the can body formed by drawing and ironing a metal plate And insert the outer die having a surface corresponding to the crossing portion of the polyhedron and the boundary ridge line and the surface on which the convex unit array corresponding to the concave concave surface of the structural unit surface is formed, and sandwich the can body part The inner and outer molds are rotated and pressed to fill the can containing the polyhedral wall in the can body, and after filling the contents containing inert gas and sealed, the maximum value of the can internal pressure is 4 kg / cm ² or more and 7 kg / A polyhedral wall is formed by performing a heat treatment in a range of ² cm ² or less, and inflating the recessed portion of the structural unit surface outward to form a substantially smooth surface displaying the polyhedral wall on the body surface. Manufacturing method of the positive pressure can formed in the part.